1. Field of the Invention
Applicant's invention relates to the human assisted parturition of calves and other livestock offspring.
2. Background Information
While human interaction by way of selective breeding has produced larger, more disease-resistant, and generally more desirable specimens of domesticated livestock, such intervention has had the deleterious effect of rendering many species virtually incapable of non-assisted parturition.
A number of methods and apparatuses have been devised over the years for use in assisted parturition.
U.S. Pat. No. 1,326,800 issued to Spruyt discloses an apparatus including ropes which are tied at first ends to the legs of a calf and which are connected to a capstan at their other ends. A calf is then pulled through the birth canal as the ropes are pulled by turning the capstan.
U.S. Pat. No 1,604,714 issued to Nuesch discloses a combination of a lever having a hook eye on one end and a track with a plurality of pivotal points along its length for mating with the hook eye of the lever. The two longitudinal members of the track diverge at one end and are formed for resting against the upper thighs of a delivering cow. A rope member is attached to the four legs of the calf and to the lever at some midpoint along its length. The calf is pulled through the birth canal by pivoting the lever about successive pivotal points along the track, each time pulling the calf further through the birth canal.
U.S. Pat. No. 2,098,151 issued to Junge discloses a slip collar made of chain and attached to a longitudinal handle member. The end of the handle member having the slip collar attached thereto is inserted through the birth canal, the slip collar is positioned around a calf's forelegs and as the handle is pulled from the birth canal, the slip collar tightens around the forelegs permitting the user of the apparatus to pull the calf through the birth canal. The handle also includes an eye on the end opposite that of the slip collar which permits, by placing a rod through such eye and twisting, applying a torque to the calf and thereby rotating it along its axis for obtaining a more favorable position for parturition.
U.S. Pat. No. 2,668,539 issued to Dermody discloses an instrument for animal delivery including a flexible loop attached to one end of a flexible handle having a rigid cross member at its other end for ease of applying a traction force. The loop is simply placed around the fetus' neck and the fetus is pulled through the birth canal by applying a traction force to the cross member.
U.S. Pat. No. 2,709,438 discloses an adjustable obstetrical head snare which includes a bight of cable with a double-channeled sliding member associated with the juxtaposed cable leads thereof. The bight is placed over a fetus' head, a portion of the sliding member is positioned within the mouth of the fetus, and force is applied to the terminal ends of the cable to pull the fetus through the birth canal.
Each of the above-described apparatuses pose dangers to the fetus and/or to its mother or, in the alternative, are not particularly effective in achieving their stated objectives. In the case of the Spruyt invention, the use of slip knots or their equivalent at the ends of ropes poses a danger of crushing bones and surrounding tissues as the traction force is applied. The Neusch apparatus provides little more than an alternative source of traction force to be applied to that which is essentially a common rope attached to a fetus' forelimbs. The Junge apparatus poses a substantial danger to a fetus by virtue of lack of any control over the compressive force applied to the fetus' forelimbs resulting from the slip collar structure and by virtue of the use of chain with its propensity for crushing and abrading tissues to the detriment of the fetus and the mother.
The Dermody apparatus, includes a spring connected on one end to the loop which is placed over a fetus' head and on the other end with the cross member or handle. The spring is likely to pinch or cut the skin of the fetus or the interior surfaces of the mother's birth canal. Also, the loop placed around the head of the fetus is not adjustable and is, therefore, likely to slip from the fetus' head. The Murray apparatus poses similar dangers to those of the Junge apparatus in that there is no check on the compression exerted on the fetus and the use of cable presents hard and potentially injurious surfaces to the tissues of the fetus and of the mother.
It would, therefore, be desirable to provide a novel apparatus for assisting in the parturition of livestock, which apparatus permits a secure engagement with a fetus and is, therefore, effective in aiding in parturition. Further, it would be desirable to provide such an apparatus which would include means for checking the compressive force applied to a fetus and which would be made from materials lacking a tendency to injure the tissues of the fetus or its mother.